


Fishy business

by JellyFicsnFucks, silverryu25



Category: Undertale (Video Game)
Genre: Cute, Fluffy, Gen, Kinda?, Sans and Pap are shocked!, just brotherly relationship, mermaid Red - Freeform, silly skeletons get a pet, tiny memraid
Language: English
Status: In-Progress
Published: 2020-05-31
Updated: 2020-06-28
Packaged: 2021-03-03 00:29:08
Rating: Not Rated
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 3
Words: 2,853
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/24475795
Author URL: https://archiveofourown.org/users/JellyFicsnFucks/pseuds/JellyFicsnFucks, https://archiveofourown.org/users/silverryu25/pseuds/silverryu25
Summary: Sans and Papyrus go to a fair. Papyrus wins a goldfish! Totally normal, nothing strange about that!Except this goldfish is the wrong colour and...
Relationships: Papyrus & Sans (Undertale)
Comments: 79
Kudos: 130





	1. Chapter 1

**Author's Note:**

> Hello! :D
> 
> This is a story by JellyFicsnFucks and me, where Jelly wrote the first part (until the line) and I was cuted out so bad I had to add some to it... then bug Jelly into letting me post it >:D
> 
> Jelly was inspired by Muskka's art of mer Red you can find [here](https://twitter.com/Muskka_mu/status/1022598727716884480) (though I imagined Red smaller then that XD)
> 
> Hope you like!

Papyrus wasn’t sure -what- exactly he was holding in the little plastic bag he’d won at the carnival. The woman told him he’d gotten the grand prize and handed him a goldfish but this fish was oddly colored. A deep crimson… red.

...Or maybe it was a trick of the paper lanterns outside and the flashing lights from the different games set up around the park.

“cool fish, bro.” Sans said with a genuine smile, a bit too busy with his cotton candy to notice how odd it was. The fish swam and swam in circles, as if trying to get his attention. Papyrus let it be, after all, when was the last time he’d seen his brother so happy?

They played a couple more games at the carnival before they sat at a restaurant for some real food. Papyrus poked the little plastic bag as they waited for their meal. The tiny fish was pretty cute but in the brighter light indoors revealed something new.

“Sans~… SANS?!” Papyrus slapped the table for attention, even though his brother was only a foot away.

“wha-?”

“I think my goldfish has a skull!”

“yeah,paps. lots'a animals have skulls.”

“No, Sans! LOOK!”

So the skeletons peered through the plastic and sure enough, saw the tiny little skull peering back at them. Papyrus sighed a breath he didn’t know he was holding. The red tail flickered back and forth, glad to be found. Tiny fingers pressed up against the plastic.

“Wowie…” Papyrus gulped. “Its a mermaid….”

* * *

Sans sighed as he fell back onto the couch, making sure he won’t shake his tiny companion too much.

They had rushed home as soon as they noticed the fish Papyrus won was…  _ fishy _ (heh). The absolutely minuscule mermaid couldn’t have been comfortable in that small plastic bag. Even if the bag seemed large in comparison to the little guy. Still… better safe than sorry. They had to get him a bigger space so he wouldn’t suffocate.

Could he? Suffocate? Skeleton monsters didn’t exactly need to breathe, at least not all the time, but what about a half-skeleton, half-fish monster? Was oxygen vital to maintaining his magic flow?

What did they get themselves into?

Sans rubbed his face with one hand, already bone-tired at the thought of having something that small and fragile to take care off. Could they even? There was a reason why they had a pet _rock_ instead of a more traditional… alive pet.

He took another peek at their new housemate, the little fish was swimming lazily, arms crossed and… was he pouting? Sans wasn’t sure because it was hard to see through the half murky plastic, but he thought he could see the tiniest of frowns ever and pursed lips and that was kinda cute-

“SANS?!” Papyrus’ voice boomed from the kitchen. “I HAVE FOUND SOMETHING FOR OUR NEW FRIEND. SHOULD I FILL... IT WITH COLD OR WARM WATER?”

“uhhh...” Sans didn’t expect his brother’s hesitant tone, and he froze up a bit. Thankfully, a quick glance at the mermaid gave him a hint. The little dude (was he a dude?) was wagging his hand up down, making the ‘average’ motion. Huh, did he hear and understand Papyrus? 

“try room temp bro.” Sans decided to reply, getting the tiniest thumbs up in his life. Heck, that was even cuter.

He was doomed, wasn’t he? He’s gonna spoil this tiny monster rotten.

Just as Sans felt his cheekbones warming up, a soft blush spreading over them, Papyrus ran into the room carrying some kind of a glass bowl. It wasn’t a proper fish tank, they would have to go shopping for that, but it was better than a plastic bag. Bigger too.

“HERE IT IS SANS!” Papyrus sounded proud of his work, making Sans grin up at him.

“great job, bro.” Sans shot back. “ya really  _ bowl _ me over with how cool you are.”

“NYEH!! SANS! NO PUNS” Papyrus yelled back, but Sans could see the smile he was trying to hide.

“sure bro, sure.” He offered back with a quiet chuckle.

They quickly put the bowl down, and started to open the plastic bag. It was… hard. Skeleton fingers weren’t the best at work that usually required subtlety, the bone didn’t offer as much sensory input as skin would. But Sans was slow and careful, finally managing to untie that wretched knot. But now he had a dilemma… how will he get the mermaid out of the water?

Before he could think what to try the mermaid, obviously having enough, jumped out of the water and grabbed one of his phalanges that was still hovering over the opening, making Sans flinch a bit. Thankfully, he didn’t shake the little thing off.

“fuckin’ finally!” The red merskeleton growled up at Sans. “thought i would dust in ‘dere.”

Sans stared, his mouth hanging open as Papyrus’ eyes bulged out.

_ What did they get themselves into? _

**Notes for the Chapter:**

> Talking fishes from fairs are completely normal... right?! XD
> 
> Sans and Papy will definitely have their hands fool with this little monster ;)


	2. Chapter 2

**Summary for the Chapter:**

> Sans and Papyrus try to befriend their new fishy companion. It goes… well?

**Notes for the Chapter:**

> Here is some more of this cuteness! XD
> 
> Jelly was kind enough to agree to write more of this with me so this will be a silly collab between the two of us. The idea is to do short chapters with silly events we can think up between the skele brothers and their tiny fishy Red X3 
> 
> Writing in this chapter (each part separated with a line): 1st part Jelly, 2nd part Ryu, 3rd part Jelly

Sans and Papyrus had become very cautious with their new… pet… houseguest? The small fishy had spoken and mermaid monsters were so rare in the underground they were thought of as myths. Even rarer, this one was a skeleton hybrid. It was lucky they came across him in the fair and not someone else. 

His scales shimmered in the light. Now that the small fishy had acclimated to the new water it looked like his color was coming back. The pale pink color was now brightening up to a beautiful bright red like a rose in full bloom. 

Now that he wasn’t being shaken up in the baggie, the lil mer had space to stretch. And he did it happily. The fishy swam circles around his new home. The glass bowl was a lot bigger than what he was used to. 

Papyrus and Sans sat around the table and stared inward at the fish bowl. The mermaid spoke earlier and showed signs that it understood them, but now the mer was acting like a normal gold fish and making laps around the bowl excitedly. It was hard to get it's attention and Sans was a bit at a loss for words. 

“um. so… i’m sans and this is my bro papyrus.” Sans rubbed the back of his skull feeling a bit awkward to introduce himself to the tiny fish. “what’s your name?”

Silence greeted him. Red made a small hum in his throat, happy. 

So Papyrus tried next to make his own introduction. “I AM THE GREAT PAPYRUS! AND MY BROTHER HERE IS SANS! DO YOU HAVE A NAME NEW FRIEND? I CAN GIVE YOU A NAME IF YOU DON’T HAVE ONE. HOW ABOUT PAPYRUS JR!!”

They both eagerly sit by the fishbowl and wait for it to answer, but nothing. At last the mer drops to the bottom of the bowl and rests, closing his eyes and curls into a ball to sleep. 

“... heh… guess he’s sleeping with the fishes?” 

“I HAVE SPRINKLES FOR YOU NEW FRIEND! THE PET ROCK EATS IT ALL THE TIME!” He pinches a bit and drops it in from the top. A rainbow color of sprinkles float and bob and the top of the water. 

* * *

Sans and Papyrus watched intently as the sprinkles slowly sank to the bottom of the fishbowl, wondering what their new tiny friend would do. Maybe he would talk to them again after a meal? He might be too hungry to talk, since he was stuck in that plastic bag for who knows how long.

The sprinkles slowly fell, almost looking like colorful snowflakes, gently settling down around the sleeping fish. Until one landed on his skull and all hell broke loose!

The mer uncurled, jumped and swam straight into the glass of the fishbowl with a tiny tock sound, making both Sans and Papyrus flinch in sympathy. The mer had both hands on his head, where a visible red mark started appearing, and shook his head trying to clear it. Then he looked around and noticed the sprinkles, then Sans and Papyrus staring at him.

“heh, sorry bud, didn’t expect ya to get spooked. just wanted to  _ sprinkle  _ something nice in there for you.” Sans said apologetically.

“NYEH! NO PUNS BROTHER!” Papyrus’ voice sounded a little strained, probably feeling bad for scaring his new friend. “I AM SORRY FOR SCARING YOU NEW FRIEND. I WANTED TO GIVE YOU SOME FRIENDSHIP FOOD IN YOUR SIZE. PLEASE HAVE SOME!” He added with a little bit of hope in his voice. The mer wouldn’t say no to that, right?

The fishy skeleton narrowed his sockets, looking suspicious. Or maybe his head just hurt because of the mad rush to escape? Hard to tell on a face that tiny.

He spent a little more time rubbing the sore spot on his head, floating calmly in the same spot, while observing the sunken sprinkles. The brothers kept expectant looks pointed his way, waiting with bated breaths.

Then, with the tiniest shrug, the mer finally swam down and grabbed one of the sprinkles, a blue one. He cautiously brought it up, almost like he was afraid it would hurt him, and sniffed. Suddenly, his eyelights lit up, turning into tiny red stars and he chomped down onto the sprinkle, munching it up in two quick bites, then licked his chops and looked around.

Without another pause he started zooming around the fishbowl, like he had before he fell asleep, and started grabbing and eating up the sprinkles, one by one, until the bowl was completely devoid of the colorful decorations. 

When he noticed he was done, the little guy swam to a stop in the middle of the bowl, both tiny hands rubbing his, now a lot bigger, belly with a happy expression on his face. Quickly, he raised a hand to his mouth and let out an air bubble that promptly floated up to the surface where it hung for a few moments then popped, letting out a tiny burp. 

Sans and Papyrus just gave each other looks, stars in their sockets, as the mer curled back at the bottom of his new home.

* * *

“Heh, the lil guy was really hungry.” Sans makes a pre-emptive chuckle preparing for another pun. “guess he was-” His brother rolls his eyes in his skull and quickly slaps a mitten over Sans’s mouth. 

“STOP SANS! YOU'LL SCARE OUR NEW FRIEND. YOU REALLY NEED TO SCALE BACK THE FISH PUNS!” 

Sans made an extra giddy chuckle from behind the mitten. It takes a while before Papyrus fully understands the pun he just made. “NO! NOW I AM PUNNING TOO!?” He stomps out the kitchen. “YOUR TOMFOOLERY IS CONTAGIOUS SANS! COME NOW, LET OUR NEW FRIEND SLEEP IN PEACE!” 

“heh, okay bro.”

The two turn off the kitchen light and head upstairs. The small fishy peeks an eye open when they are finally gone. 

**Notes for the Chapter:**

> Seems Red is into friendship food XD  
> Gotta wonder if he'll like Papy's spaghetti?
> 
> If you guys have any ideas for what you'd like to see these three dorks do, leave a comment and we might pick some ;3


	3. Chapter 3

**Summary for the Chapter:**

> Some shopping is done for the little fishy friend :3

**Notes for the Chapter:**

> Some more fishy shenanigans. The skele bros decide to help Red feel more at home. Let’s see how that goes.
> 
> Writing in this chapter: 1st part Ryu, 2nd part Jelly

Sans was walking lazily behind his brother, hands tucked into his hoodie pockets, grin relaxed and sockets half closed. Unlike Sans, Papyrus kept nervously rubbing his hands and turning to look at his lazy small brother, his expression tight and worried, making Sans give him a relaxed wink. The lazy skeleton knew what his brother was worrying about and he was having a lot of fun with this prank.

Sans was carrying an occupied fish bowl on the top of his head as he wobbled behind Papyrus.

“SANS!” Papyrus finally broke, making Sans’ grin widen. “DO YOU  _ HAVE  _ TO CARRY OUR MERMAID FRIEND LIKE THAT?”

“aw, what’s wrong bro?” Sans teased, sockets half closed looking as relaxed as ever. “ya know i like  _ usin’ my head  _ for important stuff.” He finished with a wink, making Papyrus let out an indignant NYEH!

He was enjoying teasing his brother, but he was being very careful, despite how relaxed he looked. Sans kept a strong grip on the bowl with his blue magic, making sure it wouldn’t budge. He wouldn’t let it drop if he got hit by a car. The cargo inside was way too precious for that.

Having enough Papyrus spun around and grabbed the bowl, making Sans flinch as the magic held on for a moment before he remembered himself and let it dissipate. That moment was enough for Papyrus to realize what Sans had been doing and his expression relaxed a bit, turning fond. He would get revenge for that prank later, for now he was just happy Sans was careful with their companion.

“I DO NOT TRUST THAT HEAD OF YOURS, SANS!” Papyrus announced as he turned back to his goal and sped up. “IT IS FULL OF THOSE AWFUL PUNS AND THIS NEEDS A HANDS ON APPROACH. NYEHEHEHE!”

Sans’ grin almost split his head as he watched Papyrus’ cackle away at his word play. He continued his slow pace, still somehow keeping up with his enthusiastic brother, as they neared their goal.

A monster pet shop.

It was time to get their little friend things he would need, and the best place for that was a pet shop. Maybe they could even find out some stuff about the mermaid? Like how come he could talk and why didn’t he want to? Or what does he prefer to eat? Does he need some kind of… house? Lair? Burrow? Cave? What are those called when underwater?

He noticed that their tiny fish friend (he really needed a name cause this was getting tiring) looked excited. Sans wasn’t sure if he understood where exactly they were going, if he knew what a pet shop was, but he seemed to like going outside. Sans needed to remember that.

With his lazy grin back in place he followed Papyrus inside the monster pet shop, listening to Papyrus yell in excitement. This was gonna be fun.

* * *

Sans idly looked at the lower shelves, while Papyrus browsed the top. The mer had prime real estate atop Sans’s head. He could see almost everything in the store. He swam around excitedly, having heard their conversation. They were here for him. 

_ They were going to keep him! They were going to buy him things! He was gonna have a home!!  _

The small red fish buzzed around, giddy that he wouldn’t be thrown out again. There looked to be a lot of creatively designed homes for him. One was a sunken pirate ship. Another was a castle!

The atmosphere of the pet store was really familiar. Overhead the loudspeakers played a calming ocean sound. It’s lush waves echoed throughout the bowl and the small fish felt like he was finally at peace. 

“heh, bro look. a skull. He can swim through the eye and make a home inside.” 

“PUT THAT DISTASTEFUL THING DOWN! CLEARLY THE SUPERIOR HOME IS A PINEAPPLE!” 

While the two skeletons bickered the mer was carefully eyeing the shelves for things he might want. With a tap on the glass and an excited swish of his tail he got the attention of the two. 

Outside the harsh winds of Snowdin had picked up. Sans had to tuck the fishbowl into his hoodie to make it back home. He looked like a fat lil skele with the fishbowl tucked safely in his sweater, but it was a warm place for the mer. They bought a lot of goods by the end of the day, some things Red picked out would be delivered tomorrow, but Papyrus was especially thrilled about some secret delivery that would be sent later. 

They unpacked the bags when they got home and got to work setting up a new home for their fish friend. Like before, the fishy grabbed onto his boney finger to be picked up and placed into a temporary home. Today it was one of Sans's punny coffee mugs. 

The mer angrily pouted at them, leaning over the rim of the mug. Half in the water, half out, his arms clacked against the ceramic as he boredly pounded the side of it. It wasn’t big enough to do more than sit. 

Papyrus and Sans were quickly trying to set up their friends' new home, throwing in gravel and assorted plants, to make the bowl seem a little more homely for their aquatic friend. The packaging on one of the water filters said to wait an hour for the tank to purify, then use the testing strips to check if the water was properly balanced. 

So Sans got the bright idea to carry the little mer around the house, taking the coffee mug on a tour. The mer peered over the rim of the cup and stared out at the place with awe. So this was how other creatures lived? Where were their rocks? And twigs?

The mer felt a bit safe at seeing the new surroundings. The large home didn't seem so intimidating and the monsters that took it were friendly. From over the mug he motioned for the skeleton to come down to him. 

Sans tilted his head a bit confused. He leaned in, wondering if the mer would whisper something to him. Instead he felt a tiny clack against his cheek. The mer blushed brightly, and gave him a lil skele kiss as thanks.

**Notes for the Chapter:**

> Hope you enjoyed! :D
> 
> Here is the big lottery question: what kind of house did Red pick for his tank? >:3  
> Please leave a suggestion in the comments and we'll pick one to be Red's new sleeping place in the tank! :D
> 
> There is still a bigger surprise for Red that will arrive sometime later, but for now, his home needs to be set up X3

**Author's Note:**

> *Ryu won't see this message mweh heh heh. (ﾉ^ヮ^)ﾉ*:・ﾟ✧ Silverryu is the cutest bean for continuing this.  
> And I'll fite anyone who says otherwise! (╯°Д°）╯︵/(.□ . )  
> Thankies for love and support. I cry. ♥♥♥ you da best.
> 
> * Nuuuuuuuu!! Jelly is the real cutie here! And imma fight on that (ง •̀_•́)ง   
> Jelly deserves all the love! (≧◡≦)♥  
> You da best!!


End file.
